Add description for setNoticeCallback method

Co-authored-by: KentarouTakeda <takeda@youmind.jp>

Author: Girgias

reference/pdo_pgsql/pdo/pgsql/setnoticecallback.xml

@@ -12,7 +12,11 @@
    <methodparam><type class="union"><type>callable</type><type>null</type></type><parameter>callback</parameter></methodparam>
   </methodsynopsis>
   <simpara>
-   Description.
+   Set a callback to handle notice and warning messages generated by the backend.
+   This includes messages emitted by PostgreSQL itself,
+   as well as those raised by user-defined SQL functions using <literal>RAISE</literal>.
+   Please note that the actual receipt of these messages
+   depends on the backend setting <literal>client_min_messages</literal>.
   </simpara>
  </refsect1>